Two thousand dollars a pound seems like a lot to pay for a mushroom. It really does. Yes, October marks the start of white-truffle season, the time of year when the rare mushrooms are showered on dishes, signifying luxury to even the most jaded palates. One of Daniel Boulud's favorite stories involves Puff Daddy, as he was known at the time, urging the chef to "shave that bitch" onto his food; Boulud told me that he obliged (as, I'm sure, the bill mounted accordingly).

Truffles are rare. The white ones are only available a couple of months of the year, almost exclusively from one part of Italy, where they must be foraged by special pigs, and there are fewer of them, and of lesser quality, every year. They are, in short, the perfect luxury commodity, precious and getting more so all the time. Whether they are worth the money has a lot to do with how you like to spend and why you go to dinner. Which makes them very interesting to me.

There's no question that white truffles have a unique aroma, a combination of newly plowed soil, fall rain, burrowing earthworms and the pungent memory of lost youth and old love affairs. I literally was not able to find a chef who doesn't love them. The most eloquent was Alex Guarnaschelli of Butter, a highly fashionable restaurant in New York City that caters to a moneyed clientele. The way truffles smell is "disconcerting," she says. "It conjures up images of a locker room. But the aroma deceptively conceals their complex yet delicate taste. They are sublime." Guarnaschelli shaves them over risotto or mashed potatoes, and likes them a little warm; other chefs find a little creamy or buttery pasta the perfect vehicle. They are all as careful in their handling of it as a museum curator moving the Mona Lisa. This is a mushroom, mind you. (See "Twitter Streams of the Food Gods: Pretty Thin Soup.")

I wondered if, given how expensive truffles are and how far the Italian imports have to travel to reach most restaurants, they might become out of fashion in the current local-foods-loving, recession-hobbled culinary scene. I asked John Magazino of Primizie Fine Foods, one of the leading truffle importers in the country, if he was noticing any decrease in demand. "If anything, there's more," he told me, adding that the global appetite for white truffles, especially the ones from around Alba, Italy, has utterly outstripped the harvest. From Macau to Dubai to Chicago, there are never enough to go around. And, Magazino explained, there are fewer truffles every year, thanks to global warming and the leeching of fungicides into the soil, among other things. "There's been a general decline over the last 15 years in both quantity and quality of white truffles," he told me. "And the market just has to live with that, because truffles can't be faked or formulated."

Wait, what? How is it possible? We can clone whole animals and sequence the human genome, but we can't figure out a way to grow mushrooms in a hothouse? Apparently, it's true. While the inferior black or Périgord truffle can be cultivated, right now there is no other way to get white ones except to set pigs (and, in recent years, dogs) loose on the hills of the Italian piedmont, snorting with pleasure and excitement at the thought of finding precious fungi that their owners won't allow them to eat.

Isn't that an incredible image? It cheers me that we still have to use such a medieval system. If truffles could be put into mass production and sold at Whole Foods, they'd be cheaper, but their mystique would evaporate, and with it much of their value to the world. Now I have something to aspire to, to talk about, to dream of and to save up for. In a world where essentially everything is available to everybody at all times, give or take a few seasonal vegetables, that rarity is luminous and riveting. It makes the small number of truffles that we are getting one of the few luxuries that deserve the name. You can buy a Louis Vuitton purse at an outlet mall and an Aston Martin on eBay. But you can't get truffles without major trouble  and access to Magazino or someone like him. (See pictures of food as pop culture.)

It's not that science hasn't tried. Key chemical compounds intrinsic to the aroma of truffles have been isolated and are sold as truffle oil, a substance so stinky you can smell it from a mile away. Black truffles are in mass production in China and are supposedly getting better all the time. (I'm still waiting; the ones I've tried were gnarly.) All these futile efforts only make you want the good white truffles all the more, the way a series of problematic relationships only makes you long all the more for the Girl You Left Behind. It's really a kind of romanticism.

Still, it occurs to me that, given the movement toward local food and the abundance of magnificent American fungi, there ought to be somebody who will stand up for the perfect morel, say, which is to spring what white truffles are to fall in the mushroom world. I asked Tom Colicchio, famed for his use of mushrooms and in a sense the father of the current new-naturalism movement, whether he found in his domestic mushroom garden any substitute for the Pearl of Alba. "I love all the mushrooms that I cook with," the chef said, "but white truffles are something completely different." He paused, searching for a way to emphasize why they matter so much. He found it in the words everybody uses: "There's nothing else like them."

Ozersky is a James Beard Awardwinning food writer and the author of The Hamburger: A History. His food video site, Ozersky.TV, is updated daily. He is currently at work on a biography of Colonel Sanders. Taste of America, Ozersky's food column for TIME.com, appears every Wednesday.